Annealing furnace



wk., l W3. l-l. A. STAPLES M4959 ANNEALING FURNACE Filed Jan. 17, 1955 4 Sheets-Sheet 2 @@p W, R3.. H. A. STAPLES Zmg ANNEALING FURNAGEl Filed Jan. 17, 1935 4 Sheets-Sheet 3 ml N' u INVENTOR mcs A. STAPLES Spth T W35 l H. A. STAPLES ANNEALING FURNACE Filed Jan. 17, 1955 4 SheebS-Sheel INVENTOR HORACE/4. 57m/:A561

Patented seisf. 17, 1935 UNITED STATES PATENT OFFICE ANNEALING FURNACE Application January 17, 1935, Serial No. 2,154

4 Claims.

My invention relates to annealing furnaces, more particularly to furnaces for' continuous dry bright annealing of metals and has for its object Ithe production of a furnace of improved construction providing for gradual and long time heating and cooling of the metal, thereby permitting operation at a lower temperature and consequently more uniform anneal. This is very important and Valuable in the annealing of wire on spools or reels in that it avoids sudden expansion of the material thereby causing displacement of the wire, with consequent sticking on the spool.

A further object of my invention is to produce a furnace of large production capacity in comparatively small floor space.

So far as I am aware, all previous continuous dry bright annealing furnaces have either been of comparatively small capacity or have required excessive amount of iioor space.

By my construction I secure gradual long time heating and cooling in non-oxidizing atmosphere, and am able to concentrate an apparatus capable of large production capacity in comparatively small floor space; and because of the tendency of the heated gas to rise, I insure a cold discharge, thereby preventing discoloration of the metal.

The foregoing and other features of my invention will now be described in connection with the accompanying drawings forming part of this specification in which I have represented my annealing furnace in its preferred form, after which I shall point out in the claims those features which I believe to be new and of my own invention.

In the drawings,

Figure 1 is a plan sectional View of my annealing furnace in part section.

Figure 2 is a vertical section of my furnace along the line 2-2-2, Figure l.

Figure 3 is an elevation in part section along the line 3--3, Figure 1.

Figure 4 is a typical section of roller conveyor, showing relative location of rollers and the electrical heating element.

Figure 5 is a detail plan of means used for controlling the discharge of pans from the conveyor one at a time.

Figure 6 is an elevation of detail shown in Figure 5.

In the carrying out of my invention, I provide a continuous vertical spiral roller conveyor Ill enclosed in a gas tight annular space between an outer casing Il and an inner casing i2.

In Figure 4 I have a typical section showing the vertical spiral conveyor with the rolls I3 mounted in between rails I4, with the rails l5 acting as guiding rails for the circular pans I6 which I employ to transfer the articles to be annealed through the furnace.

The upper portion of annular space is insulated 5 against heat transference by insulating material il and under the rollers i3 I provide heating elements I8 regulated by suitable pyrometer control i9 of the usual type and ensuring gradual heating and close control of temperature. There is l0 also provided a horizontal insulated portion 2G between the upper and lower portions of the ane nular chamber to retard the transfer of heat from the upper o-r heating Zone to the lower or cooling zone. In my preferred form of construction my 15 annular chamber is gas tight and in order to ensure this I may provide water seals 2l at the bottom edges of the casings Ei and i2. However, I may dispense with this detail and use bolted joints well packed to prevent leaks.

At the top of the annular space I provide an inlet opening 22, and at the bottom of the annular space I provide an outlet opening 23. Both of these openings are sealed against ingress of air by gas locks 24 and 25. These locks being similar 25 I will describe only one, but will number similar parts of both locks with like numbers. These locks consist in the design shown of simple vestibules provided with two gas tight doors 26 and 2l operated by any means 28 so that when one door 30 26 is closed, 21 is opened and vice versa. These doors may also be controlled so that when material is being discharged from the bottom through vestibule 25 material to be annealed is being charged through vestibule 24. These vestibules 35 may be provided with expansion joints 29 to accommodate any misalignment due to expansion. For convenience in handling material, I may connect these gas locks with .elevating and conveying machinery and in the preferred form shown I 40 employ an elevator 30 and a roller conveyor 3 i I may also employ a direct lift 32 to facilitate the loading and unloading of the material, to elevate the loading platform 37 to a convenient working height. 45

It will be readily understood that the detail of the gravity conveyor and the detail of the lift will of necessity be modified to suit local conditions and I may dispense with the lift 32 or place the conveyor 3l at a different elevation. 50

In the discharge opening 23, I provide pawls @il operated by fluid operated pusher 4l or manually operated mechanical means so that when one pawl goes forward the other is withdrawn to control the discharge of the finished product and in- 55 sure only one batch of material to enter the discharge gas lock at a time.

The elevator 30 may be of any type but preferably the cage 34 should run in a closed shaft 35 and may be made substantially gas tight within the shaft by packing 36. At the upper level of the cage I may provide a pusher 45 to aid in advancing the pan to the gas lock 24.

A safety valve 46 is provided at the top of the annular space to guard against excessive gas pressure.

The lower part of the annular space may be cooled by the action of air or a water spray on the uninsulated portion of the casings Il and I2 and duct 5| is provided for the introduction of air to the inner casing.

I operate my annealing furnace as follows: The articles to be annealed are loaded on pans I6 (I show circular ones in the drawings) and one of these pans is entered into the gas lock 24 by the aid of pusher 45. At the time of loading the pan in the inlet lock 24, I withdraw a pan of annealed metal from the discharge lock 25, the pawls 49 permitting the withdrawal of only one pan at a time. This pan of nished product is unloaded and reloaded on conveyor 3| and returned to inlet by the elevator 3i). It will be readily understood that there is a continuous line of pans on the spiral conveyor.

In order to obtain the best results, steam or gas atmosphere is maintained in elevator 30 and during the travel of the cage to the upper level the material is washed free from contained air. In the annular space a gas atmosphere is maintained and the metal is heated to annealing temperature by the electric heating elements it in the upper or hot zone of the annular chamber. After the metal leaves the hot zone and enters the lower or cold zone the metal gradually cools off so that when discharged it is below a discoloring temperature.

While my furnace is especially designed for the annealing of copper wire on reels or spools,

or coils, it is obvious that this furnace may be used for annealing of metal, either ferrous or non-ferrous in any form within the space limitation of the furnace or for normalizing nitriding or other heat treatment of metal.

I wish it distinctly understood that my annealing furnace herein described and illustrated is in the preferred form in which I desire to construct it and that changes or variations may be made as may be convenient or desirable without departing from the salient features of my invention and I therefore intend the following claims to cover such modifications as naturally fall Within the lines of invention. I claim:

1. A heat treating furnace comprising a vertical annular gas tight chamber, a spiral gravity conveyor mounted therein, said chamber divided into heating and cooling zones, a heating element to heat the heating zone, gas locks at the exit and entrance of the chamber, and conveying mechanism connecting the exit and entrance locks.

2. The device of claim 1 with the heating element located under the conveyor in the heating zone.

3. The device of claim l including pans for conveying articles to be heat treated through the furnace, double acting control pawls for control of the discharge of the articles from the furnace one at a time.

4. A heat treating furnace comprising a con- 5) tinuous roller gravity spiral conveyor within a vertical annular gas tight casing, means to insulate the upper zone of the casing against heat transference, means to supply heat to the upper zone, means to control the heat within that zone, means to cool the lower zone of the casing, an entrance to the top of the hot Zone provided with a vestibule, an exit at the bottom of the cool Zone provided with a vestibule, means to simultaneously open and close the vestibules, means to regulate the flow of material into the vestibule.

HORACE A. STAPLES. 

